Liquid crystal device having metal light shielding layer with portions at different potentials

ABSTRACT

The present invention provides a liquid crystal display device which is capable of suppressing occurrence of an electric field between a metal light shielding layer and a metal interconnecting layer in a peripheral circuit portion, and preventing disconnection of the metal interconnecting layer due to corrosion, and which has improved reliability under conditions where light and heat are present. In the liquid crystal display device, a metal light shielding layer is formed in a pattern reverse to a metal interconnecting layer  13  on the metal-interconnecting layer on the driving substrate side. The potential of the metal light shielding layer is set to the same potential as the potential Vss of the metal interconnecting layer. On the metal light shielding layer is provided a transparent electrode through a flattening film. The transparent electrode is set to the same potential (=the potential of auxiliary capacitor or capacitance Cs) as a counter electrode on the counter substrate side. Since no potential difference occurs between the metal light shielding layer and the metal interconnecting layer, even under conditions where water, impurities, light and heat are present, no chemical reaction (corrosion) takes place due to the occurrence of an electric field, thereby eliminating the possibility of disconnection of the metal interconnecting layer.

RELATED APPLICATION DATA

[0001] This patent is a divisional application of U.S. Ser. No.08/931,787 filed on Sep. 17, 1997. Moreover, this patent claims priorityto Japanese Application No. P08-267815, filed Sep. 18, 1997. Both ofthese applications are incorporated by reference to the extent permittedby law.

BACKGROUND OF THE INVENTION

[0002] The present invention includes a liquid crystal display device,for example, used for a VTR (Video Tape Recorder) with a cameraintegrated thereto, a liquid crystal projector and the like, andparticularly to a liquid crystal display device having a so-called onchip black matrix (optically compensated birefringence or OCB) structurein which a metal light shielding layer referred to as a black mask isprovided on the driving substrate side.

[0003] In recent years, as an electronic apparatus with a liquid crystaldisplay device, such as a liquid crystal projector, has beenpopularized, the liquid crystal display device has increasingly beenrequired to have high performance, and improvement to achieve a liquidcrystal display device having higher definition and higher luminance hasprogressed. Such a liquid crystal display device conventionallycomprises a substrate (referred to as a “driving substrate” hereinafter)on which pixel electrodes, thin film transistors (TFTs) for controllingthe respective electrodes, auxiliary capacitor or capacitance Cs etc.are formed, a substrate (referred to as a “counter substrate”hereinafter) on which a color filter (in the case of a color liquidcrystal panel), a metal light shielding layer (black mask), etc. areformed, and a liquid crystal layer held between both substrates.

[0004] Although the liquid crystal display device having the aboveconstruction requires precise alignment between the driving substrateand the counter substrate which are spaced, precise alignment becomesdifficult as the definition of pixels increases. Therefore, a so-calledon chip color filter structure is proposed in which a color filter isformed on the driving substrate side (refer to Japanese PatentUnexamined Publication No. 254217). In this on chip color filterstructure, since the color filter is overlapped with each of the pixelelectrodes, no parallax occurs between the pixel electrodes and thecolor filter, and the effective opening ratio of the pixel portion canbe increased, as compared with a conventional structure in which a colorfilter is provided on the counter substrate side. There is also theadvantage that since substantially no error occurs in alignment betweenthe pixel electrodes and the color filter, a high opening ratio can bemaintained even if the pixel portion becomes fine. Besides the on chipcolor filter structure, in order to increase the effective opening ratioof the display device having a so-called on chip black matrix structurehas recently been proposed in which a metal light shielding layer (blackmask) is also formed on the driving substrate.

[0005]FIG. 6 shows a sectional structure of the peripheral circuitportion (including a horizontal driving circuit, a vertical drivingcircuit, etc.) around the effective pixel portion in a liquid crystaldisplay 100 having the above structure. Like the conventional effectivepixel portion, the conventional peripheral circuit portion comprises aliquid crystal layer 118 held between a driving substrate 110 and acounter substrate 120. On the driving substrate 110 is formed a patternof a polycrystalline silicon film 111 as a semiconductor thin film whichconstitutes the TFTs, and an insulating film (Si02) 112 is formed on thepolycrystalline silicon film 111. On the insulating film 112 is formed ametal interconnecting layer 113 comprising aluminum (Al). The potentialof this metal interconnecting layer 113 is set to potential Vss. On themetal interconnecting layer 113 are laminated in turn interlayerinsulating films 114 a and 114 b. On the interlayer insulating film 114b is formed a metal light shielding layer (black mask) 115 having apattern reverse to the metal interconnecting layer 113, and a flatteninglayer 116 is formed on the pattern of the metal light shielding layer115. On the other hand, on the counter face of the counter substrate 120is formed a counter electrode 119. The liquid crystal layer 118 is heldbetween the counter electrode 119 and the driving substrate 110.

[0006] In the liquid crystal display device 100, the metal lightshielding layer 115 on the driving substrate side is set to the samepotential as the potential of the counter electrode 119 on the countersubstrate side and an auxiliary capacitor or capacitance Cs of the pixelportion. This is a measure for preventing application of a DC voltage tothe liquid crystal layer 118 held between the driving substrate 110 andthe counter substrate 120. However, not only the effective pixel potion,but also the metal light shielding layer 115 on the peripheral circuitportion are set to the same potential. Therefore, a strong electricfield occurs due to a potential difference between the metal lightshielding layer 115 and the metal interconnecting layer (Al wiringlayer) 113 at potential Vss, and impurity ions present in the peripheryare attracted. As a result, water chemically reacts with aluminum (Al)on the cathode (the metal interconnecting layer 113) side, therebycausing disconnection due to corrosion of aluminum. The metal lightshielding layer 115 on the peripheral circuit portion is formed in apattern reverse to the metal interconnecting layer 113 under the metallight shielding layer 115, i.e., so that both layers do not overlap eachother, as viewed from the upper side. Therefore, in a portion where thepattern of the metal light shielding layer 115 is absent, incident lightis cut off by the metal interconnecting layer 113. Thus, in a portionwhere the pattern of the metal interconnecting layer 113 is large, largequality of light is incident, and the above chemical reaction ofaluminum is accelerated by light and heat, thereby more easily causingdisconnection. Further, this disconnection allows light irradiation ofthe active layer 11 of the thin film transistors (TFTs) provided underthe metal interconnecting layer 113, and thus has an adverse effect onthe operation, such as variation in operation points of the TFTs.Particularly, when the liquid crystal display device 100 is used for aprojector or the like, this brings about a large problem with respect toreliability. When electrical leakage from the metal interconnectinglayer 113 of the peripheral circuit portion occurs, the liquid crystaldisplay device 100 becomes defective regardless of the position ofleakage.

SUMMARY OF THE INVENTION

[0007] The present invention has been achieved in consideration of theabove problems, and an object of the invention is to provide a liquidcrystal display device which is capable of suppressing occurrence of anelectric field between a metal light shielding layer and a metalinterconnecting layer in the peripheral circuit portion to preventdisconnection of the metal interconnecting layer, and which has improvedreliability under conditions where light and heat are present.

[0008] In order to achieve the object, in accordance with an aspect ofthe present invention, there is provided a liquid crystal display devicecomprising a first substrate in which a pixel portion having a pluralityof pixel electrodes, and a peripheral circuit portion disposed aroundthe pixel portion are formed, and which comprises a metalinterconnecting layer provided in the peripheral circuit portion and setto a second potential, and a metal light shielding layer which isselectively provided in a pattern reverse to the metal interconnectinglayer in each of regions of the pixel portion and the peripheral circuitportion, and which is set to a first potential in a region correspondingto the pixel portion and set to the second potential in a regioncorresponding to the peripheral circuit portion; a second substratedisposed opposite to the first substrate with a predetermined space andhaving a counter electrode set to the first potential; and a liquidcrystal layer held between the first and second substrates. The liquidcrystal display device further comprises a transparent electrode formedon the metal light shielding layer of the peripheral circuit portion andset to the first potential.

[0009] In accordance with another aspect of the present invention, thereis provided a liquid crystal projector comprising a liquid crystal panelcomprising a first substrate in which a pixel portion having a pluralityof pixel electrodes, and a peripheral circuit portion, disposed aroundthe pixel portion are formed, and which comprises a metalinterconnecting layer provided in the peripheral circuit portion and setto a second potential, and a metal light shielding layer which isselectively provided in a pattern reverse to the metal interconnectinglayer in each of regions of the pixel portion and the peripheral circuitportion, and which is set to a first potential in a region correspondingto the pixel portion and set to the second potential in a regioncorresponding to the peripheral circuit portion; a second substratedisposed opposite to the first substrate with a predetermined space andhaving a counter electrode set to the first potential; and a liquidcrystal layer held between the first and second substrates; and opticalmeans for applying light to the liquid crystal panel and enlarging andprojecting transmitted light from the liquid crystal panel.

[0010] In accordance with a further aspect of the present invention,there is provided a liquid crystal display device comprising a firstsubstrate in which a pixel portion having a plurality of pixelelectrodes, and a peripheral circuit portion disposed around the pixelportion are formed, and which comprises a metal interconnecting layerprovided in the peripheral circuit portion and set to a secondpotential, and a metal light shielding layer which is selectivelyprovided in a pattern reverse to the metal interconnecting layer in eachof regions of the pixel portion and the peripheral circuit portion, andwhich is set to a first potential in a region corresponding to the pixelportion and set to an electrically floating state in a regioncorresponding to the peripheral circuit portion; a second substratedisposed opposite to the first substrate with a predetermined space andhaving a counter electrode set to the first potential; and a liquidcrystal layer held between the first and second substrates.

[0011] In accordance with a still further aspect of the presentinvention, there is provided a liquid crystal display device comprisinga first substrate in which a pixel portion having a plurality of pixelelectrodes, and a peripheral circuit portion disposed around the pixelportion are formed, and which comprises a metal interconnecting layerprovided in the peripheral circuit portion and set to a secondpotential, and a metal light shielding layer which is provided over theentire surface of the peripheral circuit portion to prevent entrance oflight into the metal interconnecting layer, and which is set to a firstpotential; a second substrate disposed opposite to the first substratewith a predetermined space and having a counter electrode set to thefirst potential; and a liquid crystal layer held between the first andsecond substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a sectional view showing the structure of a peripheralcircuit portion of a liquid crystal display device in accordance with afirst embodiment of the invention;

[0013]FIG. 2 is a plan view schematically showing the entireconstruction of the liquid crystal display device in accordance with thefirst embodiment of the invention;

[0014]FIG. 3 is a sectional view showing the structure of a peripheralcircuit portion of a liquid crystal display device in accordance with asecond embodiment of the invention;

[0015]FIG. 4 is a plan view schematically showing the entireconstruction of the liquid crystal display device in accordance with thesecond embodiment of the invention;

[0016]FIG. 5 is a sectional view showing the structure of a peripheralcircuit portion of a liquid crystal display device in accordance with athird embodiment of the invention;

[0017]FIG. 6 is a sectional view showing the structure of a peripheralcircuit portion of a liquid crystal display device which has beenpreviously proposed; and

[0018]FIG. 7 is a drawing showing an example of a liquid crystalprojector comprising a liquid crystal display device of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Embodiments of the present invention will be described in detailbelow with reference to the drawings.

First Embodiment

[0020]FIG. 2 shows a plan of a panel of a liquid crystal display device1 in accordance with a first embodiment of the present invention. Theliquid crystal display device 1 comprises a driving substrate 10including transparent pixel electrodes respectively arranged in a matrixfor a plurality of pixels, a counter substrate 20 including a counterelectrode 19 corresponding to the pixel electrodes and disposed oppositeto the driving substrate 10 with a predetermined space there between,and a liquid crystal layer 18 held between the driving substrate 10 andthe counter substrate. The liquid crystal display device 1 has aso-called on chip black matrix (OCB) structure in which a metal lightshielding layer 15 (black mask) is formed on the driving substrate side,for shielding the periphery of each of the pixel electrodes from light.The metal light shielding layer comprises a metal having the shieldingability, such as tungsten (W), titanium (Ti), aluminum (Al) or the like.

[0021] The liquid crystal display device 1 comprises an effective pixelportion 2, and a peripheral circuit portion 34 provided around theeffective pixel portion 2 and including a horizontal driving portion 3and two vertical driving portions 4 a and 4 b, as viewed from the upperside thereof. The effective pixel portion 2 contains the pixelelectrodes, the TFT 11 serving as a switching element for driving eachof the pixel electrodes, etc. which are provided on the drivingsubstrate 10 side. Although not shown in the drawing, an auxiliarycapacitor or capacitance line is provided along the column direction ofthe pixels to form an auxiliary capacitor or capacitance (additionalcapacitor or capacitance) Cs between the capacitor or capacitance lineand the semiconductor thin film 11 (polycrystalline silicon film) whichconstitutes the TFTs. The auxiliary capacitor or capacitance line forforming the auxiliary capacitor or capacitance Cs is internallyconnected to the counter electrode 19 on the counter substrate 20 side,which will be described below, so that both are set to the samepotential (first potential).

[0022] In this embodiment, the metal light shielding layer 15 (OCB) onthe driving substrate 10 side is set to different potentials in theeffective pixel portion 2 and the peripheral circuit portion comprisingthe horizontal driving portion 2 and the two vertical driving portions 4a and 4 b. Namely, the potential of the metal light shielding layer 15of the effective pixel portion 2 is the same as the potential of thecounter electrode 19 on the counter substrate 20 side and the auxiliarycapacitor or capacitance Cs. On the other hand, the potential of themetal light shielding layer 15 in each of the horizontal driving portion3 and the two vertical driving portions 4 a and 4 b, which constitutethe peripheral circuit portion, is the same as the potential Vss (secondpotential) of the metal interconnecting layer 13.

[0023]FIG. 1 shows an example of the sectional configuration of theperipheral circuit portion shown 34 in FIG. 2. FIG. 1 shows thesectional configuration of the vertical driving portion 4 b taken alongline I-I in FIG. 2. In the vertical driving portion 4 b, the liquidcrystal layer 18 is held between the driving substrate 10 and thecounter substrate 20, as in the effective pixel portion 2 (FIG. 2). Thedriving substrate 10 comprises, for example, a transparent substratemade of glass or the like. On the driving substrate 10 is formed apattern of a polycrystalline silicon film 11 serving as a semiconductorthin film which constitutes the TFTs, for example, by sputtering. On thepolycrystalline silicon film 11 is formed an insulating film (forexample, a silicon oxide (Si02) film) 12. on the insulating layer 12 isformed a metal interconnecting layer 13 comprising aluminum (Al) whosepotential is set to Vss (the second potential). On the metalinterconnecting layer 13 are laminated in turn an interlayer insulatinglayer (e.g., a PSG (Phosphorus Silicate Glass) film) 14 a formed by, forexample, CVD (Chemical Vapor Deposition), and an interlayer insulatingfilm (SiN (silicon nitride film) 14 b formed by, for example, plasmaCVD. On the interlayer insulating film 14 b is formed a metal lightshielding layer 15 having a pattern reverse to the metal interconnectinglayer 13. As described above, the potential of the metal light shieldinglayer 15 is set to Vss which is the same potential as the metal 14interconnecting layer 13. On the pattern of the metal light shieldinglayer 15 is provided a flattening film 16, for example, comprising anacrylic resin. In this embodiment, on the flattening film 16 is furtherformed a plate-shaped transparent electrode 17. The transparentelectrode 17 is formed at the same time as formation of the transparentelectrode in the effective pixel portion 2. It is thus possible to formthe transparent electrode 17 without changing a conventional process.

[0024] On the other hand, the counter substrate 20 comprises atransparent substrate, as the driving substrate 10, and it has atransparent counter electrode 19 formed on the surface thereof oppositeto the driving substrate 20. The liquid crystal layer 18 is held betweenthe counter electrode 19 and the transparent electrode 17 on the drivingsubstrate 20 side. The transparent electrode 17 on the driving substrate20 side is electrically connected so that the potential thereof is thesame as the potential the potential of an auxiliary capacitor orcapacitance Cs) of the counter electrode 19 on the counter substrateside.

[0025] The operation and effect of the liquid crystal display device 1in accordance with this embodiment will be described below.

[0026] As described above, in a conventional liquid crystal displaydevice (such as liquid crystal display 100 of FIG. 6), in order toprevent deterioration in the liquid crystal layer 118 held between twosubstrates 110, 120 due to application of a DC voltage to the liquidcrystal layer, the metal light shielding layer 115 (black mask) on thedriving substrate 110 side is set to the potential (=Cs potential) ofthe counter electrode 119 in both the effective pixel portion and theperipheral circuit portion. Therefore, a strong electric field occurs ina region on the peripheral circuit portion (the horizontal drivingcircuit and the vertical driving circuit), for example, in the regionshown by broken lines in FIG. 6 between the metal interconnecting layer(Al interconnecting layer) 113 at potential Vss and the metal lightshielding layer 115 at the counter electrode potential. As a result,water chemically reacts with aluminum (Al) on the cathode side, and thusdisconnection of the metal interconnecting layer might occur due tocorrosion of aluminum.

[0027] However, in this embodiment, the mask pattern of the metal lightshielding layer 15 is divided into a portion in the effective pixelportion 2 and a portion in the peripheral circuit portion including thehorizontal driving portion 3 and the vertical driving portions 4 a and 4b. Moreover, the potential of the metal light shielding layer 15 in theeffective pixel portion 2 is set to the same as the counter electrode 19and the auxiliary capacitor or capacitance Cs in order to preventdeterioration due to application of a DC voltage to the liquid crystallayer 118. On the other hand, the potential of the metal light shieldinglayer 15 in each of the horizontal driving portion 3 and the twovertical driving portions 4 a and 4 b is set to the same as Vss of themetal interconnecting layer 13. This works to prevent the occurrence ofa potential difference, as in the conventional liquid crystal displaydevice 100 of FIG. 6. Therefore, no strong electric field occurs betweenthe metal light shielding layer 15 and the metal interconnecting layer13 even under conditions where water, impurities, light and heat arepresent, thereby eliminating the possibility of disconnection of themetal interconnecting layer due to occurrence of chemical reaction,apart from a conventional light crystal display device. It is thuspossible to improve water resistance, light resistance and heatresistance of the liquid crystal display device 1 of this embodiment.

[0028] The above-mentioned construction has the possibility ofdeterioration in the liquid crystal layer 18 on the peripheral circuitportion due to application of a DC voltage thereto. Therefore, in thisembodiment, the transparent electrode 17, at the same potential as thecounter electrode 19 on the counter substrate 20 side, is provided onthe peripheral circuit portion 34 on the driving substrate side 10, asshown in FIG. 1. This prevents the application of a DC voltage to theliquid crystal layer 18 and thus eliminates the possibility ofdeterioration in the liquid crystal layer 18 not only on the effectivepixel portion 2 but also on the peripheral circuit portion 34. In theperipheral circuit portion, when electrical leakage from the metalinterconnecting layer (Al) 113 on the driving substrate 110 side occurs,the panel of a conventional liquid crystal display device 100 becomesdefective regardless of the leakage position. However, the liquidcrystal display device 1 of this embodiment causes no short circuit ifleakage occurs in the metal light shielding layer 15 set to potentialVss, thereby improving the yield of products. Furthermore, in thisembodiment, the potential of the metal light shielding layer 15 in theeffective pixel portion 2 and the potential of the metal light shieldinglayer 15 in the peripheral circuit portion 34 including the horizontaldriving portion 3 and the vertical driving portions 4 a and 4 b areseparated on the metal interconnecting layer 13. It is thus possible torealize a structure having no or substantially no omission of light.

Second Embodiment

[0029]FIGS. 3 and 4 show the construction of a liquid crystal displaydevice 40 in accordance with a second embodiment of the presentinvention. FIG. 4 shows the plane construction of a panel 42 of theliquid crystal display, and FIG. 3 shows the sectional construction ofthe peripheral circuit portion (e.g., the vertical driving portion 4 a)of the liquid crystal display device 40. In FIGS. 3 and 4, the samecomponents as those shown in FIGS. 1 and 2 are denoted by the samereference numerals, and description thereof is omitted.

[0030] This embodiment is similar to the first embodiment in that themask pattern of the metal light shielding layer 15 is divided into aportion in the effective pixel portion 2 and a portion in the peripheralcircuit portion 34 including the horizontal driving portion 3 and thevertical driving portions 4 a and 4 b, and the metal light shieldinglayer 15 in the effective pixel portion 2 is set to the same potentialas that of the counter electrode 19 in order to prevent deterioration inthe liquid crystal layer due to application of a DC voltage thereto.However, this embodiment is different from the first embodiment in thatthe metal light shielding layer 15 in each of the horizontal drivingportion 3 and the two vertical driving portions 4 a and 4 b is providedwith no electrical contact, such as to metal interconnecting layer 13,so that the potential thereof is in a floating state, therebyeliminating the need for transparent electrode 17 in the peripheralcircuit portion 34 on the driving substrate 10 side.

[0031] In the above construction, even if chemical reaction due to anelectric field takes place between the metal light shielding layer 15and the metal interconnecting layer 13, no charge moves into the metallight shielding layer 15 in a floating state. Therefore, chemicalreaction of water and a metal (Al) is suppressed even under conditionswhere water, impurities, light and heat are present, and occurrence ofdisconnection of the metal interconnecting layer 13 due to corrosion canthus be prevented. It is thus possible to improve the water resistance,light resistance and heat resistance of the liquid crystal displaydevice of this embodiment. Other effects are the same as the firstembodiment.

Third Embodiment

[0032]FIG. 5 shows the sectional construction of the peripheral circuitportion 34 (e.g., the vertical driving portion 4 a or 4 b) of a liquidcrystal display device 50 in accordance with a third embodiment. In FIG.5, the same components as those shown in FIGS. 1 and 2 are denoted bythe same reference numerals, and description thereof is thus omitted.

[0033] This embodiment is different from the first and secondembodiments in that a metal light shielding layer 51, whose potential isset to the same potential as the potential (=Cs potential) of thecounter electrode 19 on the counter electrode 20 side, is formed overthe entire surface of the peripheral circuit portion 34 including thehorizontal driving portion 3 and the two vertical driving portions 4 aand 4 b.

[0034] In this construction, incident light is completely cut off by themetal light shielding layer 51 in the peripheral circuit portion 34, andthus light, among other factors which accelerate the chemical reaction,can be removed. Also since the metal light shielding layer 51 cansecurely prevent entrance of water into the metal interconnecting layer13 provided under the metal light shielding layer 51, layer 51 can thussuppress occurrence of water as a reactant. In this embodiment, it isthus possible to suppress chemical reaction and prevent occurrence ofdisconnection of the metal interconnecting layer 13, as in the aboveembodiments. Therefore, it is possible to improve the light resistanceand water resistance of the liquid crystal display device 50 of thisembodiment. In this embodiment, since the active layer 11 of thepolycrystalline silicon thin film which constitutes the TFTs in theperipheral circuit portion 34 is completely shielded from light, it ispossible to prevent the adverse effect of varying the operation pointsof the TFTs.

[0035] Although the present invention has been described above withreference to the embodiments, the present invention is not limited tothese embodiments, and various modifications can be made within theequal range of these embodiments. For example, although the aboveembodiments relate to the horizontal driving portion 3 and the verticaldriving portions 4 a and 4 b in the peripheral circuit portion, themetal interconnecting layer 13 (Al interconnecting layer) at potentialVss is included not only in these driving portions but also in a levelconversion portion, a uniformity improving circuit portion, etc.Therefore, if the metal light shielding layer (15 or 51) on theseportions is formed according to one of the first to third embodiments,the above-described effect can be further improved.

Fourth Embodiment

[0036]FIG. 7 shows a liquid crystal projector 700 comprising a liquidcrystal display device of the present invention in accordance with anembodiment of the invention.

[0037] Referring to FIG. 7, a liquid crystal projector 700 comprises alight source 701, a converging lens 702, a liquid crystal panel 703, aprojection lens 704 and a screen 705. The light source 701 and theconverging lens 702 function as a light emission portion 710, and theliquid crystal panel 703, the projection lens 704 and the screen 705function as an image formation portion, an image enlarging portion and adisplay portion, respectively. The liquid crystal panel 703 is providedfor each of the three primary colors R, G and B, and lights modulated bythe respective liquid crystal panels are synthesized and then projectedon the screen 705 by a single projection lens 704. In this case, a colorseparation optical system and a color synthesizing optical system arealso provided.

[0038] In the liquid crystal display device 1 of the first embodiment,since the potential of the metal light shielding layer 15 in theperipheral circuit portion 34 is set to the same potential as the metalinterconnecting layer 13, no potential difference occurs between themetal interconnecting layer 13 and the metal light shielding layer 15,and the occurrence of an electric field between these layers is alsosuppressed. Therefore, unlike conventional liquid crystal display device100 of FIG. 6, there is no possibility that disconnection of the metalinterconnecting layer 13 occurs due to chemical reaction, and the effectof improving reliability is exhibited.

[0039] In the liquid crystal display device 40 of the second embodiment,since the potential of the metal light shielding layer 15 in theperipheral circuit portion 34 is set to a floating state, even ifchemical reaction takes place due to the electric field occurringbetween the metal interconnecting layer 13 and the metal light shieldinglayer 15, no movement of charge occurs, and chemical reaction issuppressed. Therefore, there is no possibility of disconnection of themetal interconnecting layer 13, and the effect of improving reliabilityis exhibited.

[0040] In the liquid crystal display device 50 of the third embodiment,since the metal light shielding layer 51 is provided over the entiresurface of the peripheral circuit portion 34, and the potential of themetal light shielding layer 51 is set to the same as the counterelectrode 19 on the counter substrate 20 side, incident light iscompletely cut off by the metal light shielding layer 51 in theperipheral circuit portion 34, and light, among other factors whichaccelerate chemical reaction, is removed. Also it is possible to prevententrance of water into the metal interconnecting layer 13 and thussuppress occurrence of water as a reactant. Therefore, there is nopossibility of disconnection of the metal interconnecting layer 13, andthe effect of improving reliability is exhibited.

What is claimed is:
 1. A liquid crystal display device, comprising: afirst substrate divided into a pixel portion and a peripheral circuitportion; a plurality of pixel electrodes within the pixel portion; ametal interconnecting layer providing metal interconnects in a firstpattern over the pixel electrodes at least in the pixel portion, themetal interconnecting layer held to a second potential; an insulatinglayer over the metal interconnecting layer; a metallic light shieldinglayer having a second pattern at least within the pixel portion which isinverse to the first pattern, the metallic light shielding layer beingheld to a first potential at least within the pixel portion; a secondsubstrate opposite the first substrate with a predetermined spacetherebetween; and a liquid crystal layer in the predetermined space,wherein the metallic light shielding layers within the peripheralcircuit portion is held to the first potential.
 2. A liquid crystalprojector comprising: a liquid crystal panel comprising: a firstsubstrate divided into a pixel portion having a plurality of pixelelectrodes and a peripheral circuit portion disposed around the pixelportion; a metal interconnecting layer provided in the peripheralcircuit portion and set to a second potential, the metal interconnectinglayer providing metal interconnects in a first pattern on the pixelelectrodes at least in the pixel portion; an insulating layer over themetal interconnecting layer; a metal light shielding layer which isselectively provided in a second pattern inverse to that of the firstpattern of the metal interconnecting layer in each of the pixel portionand the peripheral circuit portion, the metal shielding layer set to afirst potential in a region corresponding to the pixel portion and setto the second potential in a region corresponding to the peripheralcircuit portion; a second substrate disposed opposite to the firstsubstrate with a predetermined space therebetween and having a counterelectrode set to the first potential; a liquid crystal layer heldbetween the first and second substrates; and optical means for applyinglight to the liquid crystal panel and enlarging and projectingtransmitted light from the liquid crystal panel, wherein the lightshielding layer within the peripheral circuit portion is held to thefirst potential.